1. Field of the Invention
The present invention relates to an on-vehicle display system (e.g., display system for an instrument panel) to be implemented on a moving object that can be controlled, such as vehicles.
2. Description of the Related Art
In recent years, an on-vehicle instrument panel display system, which displays vehicle states such as vehicle speed and engine revolution speed, as well as displays information such as navigation image and CCD picture on a display panel within an instrument panel of vehicles or the like, has been suggested.
For example, as shown in FIG. 3, an on-vehicle wide display 1010 disclosed in Japanese Unexamined Patent Application Publication No. 9-123848 is connected with an information processing device 1016, via an image processing device 1012 having a VRAM or the like. The information processing device 1016 includes a CPU that performs predetermined arithmetic processing; a ROM on which a processing program is stored; and I/O interface, connected thereto. Information is provided from a navigation system 1022, a traffic information communication system 1024, a monitoring system 1026, a sensor system 1028, and a diagnostics system 1030 to the information processing device 1016. The information processing device 1016 determines driving conditions based on the above information and receives required information, and then displays various information items on the wide display 1010 via the image processing device 1012.
Furthermore, as shown in FIG. 4, an instrument panel display system disclosed in International Patent Publication, WO 2006/022191 A1 includes an LSI 102, CAN microcomputer 103, and image memory 104, in a display platform section 101 thereof. To the LSI 102, the CAN microcomputer 103 and image memory 104 are connected via CPU buses 107 and 109, respectively. The CAN microcomputer 103 receives information about the vehicle state via a LAN for CAN 105 and then controls the image data processing that is performed in the LSI 102. Also, image data from a port 6 is inputted into the LSI 102. After being subjected to size processing or the like in the LSI 102, the image data is sent to a memory bus (not illustrated), and then stored in the image memory 104. An imaging controller 118, to which the memory bus is connected, is connected to the control bus 107. The control bus 107 is controlled by the CAN microcomputer 103.
In this arrangement, the CAN microcomputer 103 shown in FIG. 4 judges a vehicle state (e.g., speed, engine revolution speed, oil amount, door state, and state of the air conditioner) based on the vehicle data sent from the LAN for CAN. Then, based on the judged vehicle state, the CAN microcomputer 103 judges whether the layout needs to be changed. If the layout needs to be changed, the CAN microcomputer 103 decides the display layout according to the judged vehicle state. And then the CAN microcomputer 103 activates a layout creating program. At this time, the CAN microcomputer 103 activates a layout creating program corresponding to the decided display layout. The program has been read out from a flash memory 108 and deployed on the DRAM in advance. In the flash memory 108, the layout creating programs for creating display layouts of a plurality of patterns are stored by each display layout. The program is deployed onto the DRAM when it is booted.
As explained above, based on the received vehicle data, the CAN microcomputer 103 decides which display layout to use and then activates a layout creating program for creating the decided display layout. At this point, each layout creating program contains at least information of the type of the image to be displayed (e.g., moving images of navigation display and speed meter, and still image of background image); information of the size of the image to be displayed (e.g., 640 pixel×480 pixel); and information of the location of the image to be displayed (e.g., location of a dot at the upper left, and vertical and horizontal length of the image).
Moreover, via the imaging controller 118, the CAN microcomputer 103 commands a Scaler 117 to enlarge or contract the image outputted from DVI, HDCP, or a capture buffer to the predetermined size, based on the information indicating the size of the image (the information contained in the layout creating program). The Scaler 117 enlarges or contracts the image to the demanded size and outputs it to the image memory 104.
Based on the layout creating program, the CAN microcomputer 103 outputs a control signal to a bitblt 119, thereby to cause the bitblt 119 to receive the image data from the image memory 104. The CAN microcomputer 103 also outputs a control signal via the imaging controller 118 to the bitblt 119, thereby to cause the bitblt 119 to create an image on which each image is located in the predetermined location, based on the information of the location of the image (the information contained in the layout creating program). The bitblt 119 creates a piece of image data based on the control signals. In this process, the image data goes through predetermined process via an image improvement 102a, and then is outputted to a liquid crystal panel 127. The liquid crystal panel 127 displays the image according to the image data.
However, the configuration shown in the Japanese Unexamined Patent Application Publication No. 9-123848 imposes a heavy load on the information processing device 1016, because the information processing device 1016 has to judge vehicle state after receiving various information and then display the various information items on the wide display 1010 via the image processing device 1012. And if an error or thermal runaway occurs to the CPU or the like of the information processing device 1016 due to the heavy load, this would result in a problem in which even important information of the vehicle that is required for control (e.g., speed information and warning information) cannot be displayed anymore.
Also, in the configuration shown in the International Patent Publication, WO 2006/022191 A1, there was also a problem in which the CAN microcomputer 103 suffers a heavy load because the CAN microcomputer 103 judges a vehicle state after receiving vehicle data and also creates image data, by using the LSI 102.